Fuel cell devices provide electricity based on an electrochemical reaction. Some fuel cell arrangements utilize phosphoric acid as an electrolyte. Such fuel cells are often referred to as phosphoric acid fuel cells (PAFC).
Fuel cell power plants typically include cell stack assemblies having multiple fuel cells. A manifold may be situated along at least one side of the cell stack assembly for directing reactants to the fuel cells. In some PAFCs, the manifolds are carbon steel and have to be protected from the phosphoric acid. A common approach includes electrostatically coating the manifold pan with a perfluoroalkoxy polymer resin (PFA) coating. While such coatings provide a useful acid barrier and serve as a dielectric barrier on the metal manifold pan, utilizing such coatings introduces additional expense. Multiple coating and sintering steps typically are required to develop a coating that is thick enough to be an effective barrier.
An alternative approach is suggested in U.S. Pat. No. 6,245,454. According to that document, a resin sheet may be situated inside of a manifold pan instead of applying a coating to the pan. That approach is not without difficulties because the installation technique can be cumbersome and the dimensional relationship of the resin sheet to the manifold pan has to accommodate for different thermal expansions of the materials.
It would be useful to have an acid proof dielectric layer for a fuel cell manifold that does not have the expense or complications associated with previous approaches.